A track configuration where a line reverses direction to climb or descend a steep grade that a train could not otherwise negotiate. The train pulls forward into a tail track, a switch is thrown, and the train then shoves backward up the next leg of the incline. While common in historic mountain railroading, most mainline switchbacks have been replaced by tunnels or spirals.
We've to cut the train in half to get it up the switchback at the old logging spur.
Operating a switchback requires a train to push backward for alternating segments, which severely limits train length and speed.
Related terms
Spiral
A track alignment that loops over itself to gain elevation in steep mountainous terrain.
Helper grade
A section of track steep enough to require additional locomotives to push or pull trains over the summit.
Wye
To turn a locomotive or an entire train around by navigating a triangular junction of track.